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Full-Text Articles in Engineering

Biogenic Synthesis, Photocatalytic, And Photoelectrochemical Performance Of Ag–Zno Nanocomposite, S. A. Ansari, Mohammad Mansoob Khan Dr, M. O. Ansari, J. Lee, M. H. Cho Dec 2013

Biogenic Synthesis, Photocatalytic, And Photoelectrochemical Performance Of Ag–Zno Nanocomposite, S. A. Ansari, Mohammad Mansoob Khan Dr, M. O. Ansari, J. Lee, M. H. Cho

Dr. Mohammad Mansoob Khan

The development of coupled photoactive materials (metal/semiconductor) has resulted in significant advancements in heterogeneous visible light photocatalysis. This work reports the novel biogenic synthesis of visible light active Ag–ZnO nanocomposite for photocatalysis and photoelectrode using an electrochemically active biofilm (EAB). The results showed that the EAB functioned as a biogenic reducing tool for the reduction of Ag+, thereby eliminating the need for conventional reducing agents. The as-prepared Ag–ZnO nanocomposite was characterized by X-ray diffraction, transmission electron microscopy, diffuse reflectance spectroscopy, photoluminescence spectroscopy, and X-ray photoelectron spectroscopy. The photocatalytic experiments showed that the Ag–ZnO nanocomposite possessed excellent visible light photocatalytic activity …


Impact Of Alkaline Doping And Reducing Conditions On Lafeo3, Geoffrey L. Beausoleil Ii Dec 2013

Impact Of Alkaline Doping And Reducing Conditions On Lafeo3, Geoffrey L. Beausoleil Ii

Geoffrey L Beausoleil II

Efficient and reliable materials for gas separation, syngas production, and hybrid nuclear power plants must be capable of reliably operating at a high-temperature range of 700-1000°C and under exposure to highly oxidizing and reducing conditions. Candidate materials for these applications include alkaline metal doped lanthanum ferrite.

In the first study, the impact of A site substitution by different alkaline metals on lanthanum ferrite (LMF, M=Ca, Sr, and Ba) was investigated. The study focused on thermal expansion near the Néel transition temperature and a magneto-elastic contribution to thermal expansion was identified for each sample. Iron oxidation, Fe3+ to Fe4+, was identified …


The Probabilistic Characterization Of Severe Rainstorm Events: Applications Of Threshold Analysis To Climate Change Impacts, Barry A. Palynchuk Phd Dec 2013

The Probabilistic Characterization Of Severe Rainstorm Events: Applications Of Threshold Analysis To Climate Change Impacts, Barry A. Palynchuk Phd

Barry A. Palynchuk PhD

A summary of PhD thesis, with emphasis upon storm event definition, and climate change impacts upon rainfall depth, duration, and intensity.


Scheduling For A Small Satellite For Remote Sensed Data Collection, Donovan Torgerson, Christoffer Korvalnd, Jeremy Straub, Ronald Marsh Dec 2013

Scheduling For A Small Satellite For Remote Sensed Data Collection, Donovan Torgerson, Christoffer Korvalnd, Jeremy Straub, Ronald Marsh

Jeremy Straub

Small satellites, such as CubeSats, serve as excellent platforms for the collection of data that can be supplied to a geographic information system. To serve this need, they require a robust and lightweight task scheduler due to their limited onboard power production capabilities as well as internal space restrictions. Because of these constraints, schedules must be optimized; however, the scheduling optimization process must be performed using limited processing (CPU) power.

Several considerations must be taken into account in order to make a scheduler for these systems. This poster highlights requirements such as inter-dependency of onboard systems, and limited windows of …


Roofsat: Teaching Students Skills For Software Development For Gis Data Collection And Other Activities, Jeremy Straub, Ronald Marsh, Donovan Torgerson, Christoffer Korvald Dec 2013

Roofsat: Teaching Students Skills For Software Development For Gis Data Collection And Other Activities, Jeremy Straub, Ronald Marsh, Donovan Torgerson, Christoffer Korvald

Jeremy Straub

Small Spacecraft provide an excellent platform for the collection of geospatial data. In order to enable the low-cost creation of small remote sensing space-craft in a university environment, a training pathway for students is required. The Realistic Operational Ob-ject for Facilitating Software Assessment and Testing (RoofSat) serves to provide students with experience developing software for a small satellite platform typi-cal of those used for remote sensing missions. It al-lows software to be tested with hardware that re-sponds in a similar manner to that found on the satel-lite for a fraction of the cost of development. This poster details the goals …


Openorbiter Ground Station Software, Alexander Lewis, Jacob Huhn, Jeremy Straub, Travis Desell, Scott Kerlin Dec 2013

Openorbiter Ground Station Software, Alexander Lewis, Jacob Huhn, Jeremy Straub, Travis Desell, Scott Kerlin

Jeremy Straub

OpenOrbiter is a student project at the University of North Dakota to design and build a low cost1 and open-hardware / open-source software CubeSat2. The Ground Station is the user interface for operators of the satellite. The ground station software must manage spacecraft communications, track its orbital location , manage task assignment, provide security and retrieve the data from the spacecraft. This will be presented via a graphical user interface that allows a user to easily perform these tasks.


Testing And Integration Team Project Management, Tyler Leben, Jeremy Straub, Scott Kerlin Dec 2013

Testing And Integration Team Project Management, Tyler Leben, Jeremy Straub, Scott Kerlin

Jeremy Straub

The Testing and Integration Team plays an integral role in the development of the open source CubeSat known as Open Orbiter. Like any project, the Testing Team’s project can benefit from structure and management to effectively utilize it’s time and resources. CSCI 297 teaches the skills needed to turn a good idea into successful endeavor. By applying skills such as effective planning, setting milestones, dealing with changes and supervising to an actual project, Open Orbiter has transformed from a pipe dream to a real, obtainable goal. Doing this has turned learning about project management into more that just power points …


Openorbiter Payload Software, Tim Whitney, Kyle Goehner, Jeremy Straub, Scott Kerlin Dec 2013

Openorbiter Payload Software, Tim Whitney, Kyle Goehner, Jeremy Straub, Scott Kerlin

Jeremy Straub

The Payload Software team is responsible for developing the image processing and task decomposition systems on the Open Orbiter satellite1. The image processing software performs operations to enhance the quality of the images collected by the onboard camera, specifically, mosaicking, which takes multiple images and stitches them together to make a larger image and super resolution, which takes multiple low resolution images of the same area to produce a higher resolution image2,3,4. The task decomposition part of the system decomposes tasks defined by the user into jobs that then get sent to the operating system to be performed. This system …


Project Management For The Openorbiter Operating Software Team, Kelton Karboviak, Dayln Limesand, Michael Hlas, Eric Berg, Christoffer Korvald, Jeremy Straub, Ronald Marsh, Scott Kerlin Dec 2013

Project Management For The Openorbiter Operating Software Team, Kelton Karboviak, Dayln Limesand, Michael Hlas, Eric Berg, Christoffer Korvald, Jeremy Straub, Ronald Marsh, Scott Kerlin

Jeremy Straub

OpenOrbiter is producing a 1-U CubeSat spacecraft1 to facilitate the construction of low-cost2 spacecraft by others in the future. The Operating Software team is in charge of designing and creating the software that controls most of the CubeSat’s operations such as image capturing, storage management, and temperature sensing. The project management deliverables that we have worked on as a team are the Project Definition, Work Breakdown Structure, and the Project Schedule. The Project Definition defines exactly what our project team will be developing including, but not limited to, what the team is in charge of developing, what its not in …


Ground Station Software Team Project Management, Zach Maguire, Marshall Mattingly, Christoffer Korvald, Jeremy Straub, Scott Kerlin Dec 2013

Ground Station Software Team Project Management, Zach Maguire, Marshall Mattingly, Christoffer Korvald, Jeremy Straub, Scott Kerlin

Jeremy Straub

In CSCI 297 class we partake in learning the roles of software team leads and developers. With hands on activities that get us involved in what a real manager of a software team may do such as: defining a project, planning a project, developing a work breakdown structure, estimating the work, developing a project schedule, etc. This work is performed in the context of the OpenOrbiter project which seeks to build a low-cost spacecraft1 that can be produced with a parts budget of approxi-mately $5,0002 by schools worldwide. The ground station software team’s purpose within Open Orbiter project is to …


Software For Openorbiter, Christoffer Korvald, Jeremy Straub, Scott Kerlin, Ronald Marsh Dec 2013

Software For Openorbiter, Christoffer Korvald, Jeremy Straub, Scott Kerlin, Ronald Marsh

Jeremy Straub

The software development effort for the OpenOrbiter project consists of four teams: operating software development, payload software development, ground station software development and testing. These teams are designing and developing the software required to create a turn-key spacecraft design1 which can be produced at a price point of under USD $5,000 by faculty, students and researchers world-wide2. Through this process, students are gaining valuable real-world experience3,4 in areas of indicated interest5. Each team is headed by a team lead who is responsible for conducting weekly meetings and organizing the activities of the team. During the Fall, 2013 semester, team leads …


Payload Software Design And Development For A Remote Sensing Small Spacecraft, Kyle Goehner, Christoffer Korvald, Jeremy Straub, Ronald Marsh Dec 2013

Payload Software Design And Development For A Remote Sensing Small Spacecraft, Kyle Goehner, Christoffer Korvald, Jeremy Straub, Ronald Marsh

Jeremy Straub

Scheduling for a Small Satellite for Remote Sensed Data Collection


Zakład Termicznego Przekształcania Odpadów Komunalnych W Krakowie – Założenia Projektowe I Stan Realizacji Budowy, Mateusz Rzeszutek, Robert Oleniacz Nov 2013

Zakład Termicznego Przekształcania Odpadów Komunalnych W Krakowie – Założenia Projektowe I Stan Realizacji Budowy, Mateusz Rzeszutek, Robert Oleniacz

Robert Oleniacz

The aim of this paper is to discuss the design assumptions and to determine the current status of the construction of the Municipal Solid Waste Thermal Treatment Plant (ZTPOK) in Krakow with a capacity of 220 thousand tons per year. This plant, planned to be built by the end of 2015 years, will be an important element of municipal waste management system in the area of the Municipality of Krakow. ZTPOK in Krakow will consist of the following installations: two lines of municipal solid waste incinerators based on moving grate technology, an installation of chemical solidification and stabilization of fly …


Nanohub - Crystal Viewer 2.0, Kevin Margatan, Gerhard Klimeck Nov 2013

Nanohub - Crystal Viewer 2.0, Kevin Margatan, Gerhard Klimeck

Gerhard Klimeck

nanoHUB is an online compilation of tools for simulations. Equipped with 3-D simulations and a capability to solve very complex calculations, nanoHUB provides its users worldwide with various tools to help them finish their assignments. One of the tools available is called a Crystal Viewer Tool, an advanced crystal visualization tool. This tool allows users to generate various crystal types including their every single detail. Currently, a newer version, called Crystal Viewer 2.0, is being tested prior to its release. However, this tool is lacking some important features and a GUI that is not as user friendly as expected. The …


Next Generation Crystal Viewing Tool, Zach Schaffter, Gerhard Klimeck Nov 2013

Next Generation Crystal Viewing Tool, Zach Schaffter, Gerhard Klimeck

Gerhard Klimeck

The science and engineering community is limited when it comes to crystal viewing software tools. Each tool lacks in a different area such as customization of structures or visual output. Crystal Viewer 2.0 was created to have all of these features in one program. This one tool simulates virtually any crystal structure with any possible material. The vtkvis widget offers users advanced visual options not seen in any other crystal viewing software. In addition, the powerful engine behind Crystal Viewer 2.0, nanoelectronic modeling 5 or (NEMO5), performs intensive atomic calculations depending on user input. A graphical user interface, or GUI, …


Probabilistic Verification Of Coordinated Multi-Robot Missions, Sagar J. Chaki, Joseph A. Giampapa Nov 2013

Probabilistic Verification Of Coordinated Multi-Robot Missions, Sagar J. Chaki, Joseph A. Giampapa

Joseph Andrew Giampapa

Robots are increasingly used to perform a wide variety of tasks, especially those involving dangerous or inaccessible locations. As the complexity of such tasks grow, robots are being deployed in teams, with complex coordination schemes aimed at maximizing the chance of mission success. Such teams operate under inherently uncertain conditions -- the robots themselves fail, and have to continuously adapt to changing environmental conditions. A key challenge facing robotic mission designers is therefore to construct a mission -- i.e., specify number and type of robots, number and size of teams, coordination and planning mechanisms etc. -- so as to maximize …


Characterization Of Extended And Simplified Intelligent Water Drop (Siwd) Approaches And Their Comparison To The Intelligent Water Drop (Iwd) Approach, Jeremy Straub, Eunjin Kim Nov 2013

Characterization Of Extended And Simplified Intelligent Water Drop (Siwd) Approaches And Their Comparison To The Intelligent Water Drop (Iwd) Approach, Jeremy Straub, Eunjin Kim

Jeremy Straub

This paper presents a simplified approach to performing the Intelligent Water Drops (IWD) process. This approach is designed to be comparatively lightweight while approximating the results of the full IWD process. The Simplified Intelligent Water Drops (SIWD) approach is specifically designed for applications where IWD must be run in a computationally limited environment (such as on a robot, UAV or small spacecraft) or where performance speed must be maximized for time sensitive applications. The SWID approach is described and compared and contracted to the base IWD approach.


Reflectance Anisotropy Of Gd5si2ge2 And Tb5si2.2ge1.8, S. J. Lee, Joong Mok Park, J. E. Snyder, David C. Jiles, Deborah L. Schlagel, Thomas A. Lograsso, A. O. Pecharsky, David W. Lynch Oct 2013

Reflectance Anisotropy Of Gd5si2ge2 And Tb5si2.2ge1.8, S. J. Lee, Joong Mok Park, J. E. Snyder, David C. Jiles, Deborah L. Schlagel, Thomas A. Lograsso, A. O. Pecharsky, David W. Lynch

Professor David Lynch

Reflectance difference (RD) spectra for the a–b plane of the single crystals of Gd5Si2Ge2and b–c planes of Gd5Si2Ge2 and Tb5Si2.2Ge1.8 were obtained in the photon energy range of 1.5–5.5 eV. Several peaks were observed for these crystals in the measured spectrum range. Similar features were observed in the RD spectra for the b–c planes ofGd5Si2Ge2 and Tb5Si2.2Ge1.8, while different features were observed for the a–b plane and b–c plane of Gd5Si2Ge2. The RD spectra for the crystals arise not only from the surface anisotropy but also from the bulk anisotropy due to the monoclinic structure of the bulk crystal.


Magnetic And Superconducting Properties Of Spin-Fluctuation-Limited Superconducting Nanoscale Vnx, R Zeng, J Liu, G Du, W. X. Li, J Wang, J Horvat, S X. Dou Oct 2013

Magnetic And Superconducting Properties Of Spin-Fluctuation-Limited Superconducting Nanoscale Vnx, R Zeng, J Liu, G Du, W. X. Li, J Wang, J Horvat, S X. Dou

Josip Horvat

"VNx nanoparticles and nanowires have been prepared by nitrifying V2O5 nanoparticles (NP) and nanowires (NW). The V2O5 NP and NW were synthesized by a facile hydrothermal method. Magnetic susceptibility (chi) and magnetization measurements showed long range superconducting ordering (LRSO) at the temperature of 5.8 K for NW, but there was no observation of LRSO (at least down to 2 K) for the NP sample, which is a much lower temperature than for the corresponding bulk, while both NP and NW showed the absence of long range magnetic ordering, at least down to 2 K. However, the chi data showed that …


Climate Change And Hydrological Risks Related To Railway Infrastructure In Northern Regions, Barry A. Palynchuk Phd Oct 2013

Climate Change And Hydrological Risks Related To Railway Infrastructure In Northern Regions, Barry A. Palynchuk Phd

Barry A. Palynchuk PhD

In this paper, the authors discuss the possible consequences of global warming on northern hydrology and their impacts on railway drainage infrastructure. How can we change actual design approaches, methods and standards to adapt, to reduce vulnerability and to improve resilience to climate change? Under current climate conditions, snow, ice and permafrost play a dominant role in the water balance in cold regions. Three areas can be distinguished: regions of continuous permafrost, regions of discontinuous permafrost and permafrost-free regions. To predict the potential climate change impacts on each region, the spatial analog and the climate variability analog approaches can be …


A Microfluidic Paper-Based Electrochemical Biosensor Array For Multiplexed Detection Of Metabolic Biomarkers, Chen Zhao, Martin M. Thuo, Xinyu Liu Oct 2013

A Microfluidic Paper-Based Electrochemical Biosensor Array For Multiplexed Detection Of Metabolic Biomarkers, Chen Zhao, Martin M. Thuo, Xinyu Liu

Martin M. Thuo

Paper-based microfluidic devices have emerged as simple yet powerful platforms for performing low-cost analytical tests. This paper reports a microfluidic paper-based electrochemical biosensor array for multiplexed detection of physiologically relevant metabolic biomarkers. Different from existing paper-based electrochemical devices, our device includes an array of eight electrochemical sensors and utilizes a handheld custom-made electrochemical reader (potentiostat) for signal readout. The biosensor array can detect several analytes in a sample solution and produce multiple measurements for each analyte from a single run. Using the device, we demonstrate simultaneous detection of glucose, lactate and uric acid in urine, with analytical performance comparable to …


Joint User Grouping And Linear Virtual Beamforming: Complexity, Algorithms And Approximation Bounds, Mingyi Hong, Zi Xu, Meisam Razaviyayn, Zhi-Quan Luo Oct 2013

Joint User Grouping And Linear Virtual Beamforming: Complexity, Algorithms And Approximation Bounds, Mingyi Hong, Zi Xu, Meisam Razaviyayn, Zhi-Quan Luo

Mingyi Hong

In a wireless system with a large number of distributed nodes, the quality of communication can be greatly improved by pooling the nodes to perform joint transmission/reception. In this paper, we consider the problem of optimally selecting a subset of nodes from potentially a large number of candidates to form a virtual multi-antenna system, while at the same time designing their joint linear transmission strategies. We focus on two specific application scenarios: 1) multiple single antenna transmitters cooperatively transmit to a receiver; 2) a single transmitter transmits to a receiver with the help of a number of cooperative relays. We …


Enhanced Adaptive Management: Integrating Decision Analysis, Scenario Analysis And Environmental Modeling For The Everglades, Matteo Convertino, Christy Foran, Jeffrey Keisler, Lynn Scarlett, Andrew Loschiavo, Greg Kiker, Igor Linkov Sep 2013

Enhanced Adaptive Management: Integrating Decision Analysis, Scenario Analysis And Environmental Modeling For The Everglades, Matteo Convertino, Christy Foran, Jeffrey Keisler, Lynn Scarlett, Andrew Loschiavo, Greg Kiker, Igor Linkov

Jeffrey Keisler

We propose to enhance existing adaptive management efforts with a decision-analytical approach that can
guide the initial selection of robust restoration alternative plans and inform the need to adjust these
alternatives in the course of action based on continuously acquired monitoring information and changing
stakeholder values. We demonstrate an application of enhanced adaptive management for a wetland
restoration case study inspired by the Florida Everglades restoration effort. We find that alternatives
designed to reconstruct the pre-drainage flow may have a positive ecological impact, but may also have high
operational costs and only marginally contribute to meeting other objectives such as …


An Experimental And Modeling Study Of Formaldehyde And 1,3,5-Trioxane Flame Chemistry, Jeffrey S. Santner, Francis M. Haas, Frederick L. Dryer, Yiguang Ju Sep 2013

An Experimental And Modeling Study Of Formaldehyde And 1,3,5-Trioxane Flame Chemistry, Jeffrey S. Santner, Francis M. Haas, Frederick L. Dryer, Yiguang Ju

Francis (Mac) Haas

Formaldehyde is a key species produced during oxidation of virtually all hydrocarbon and oxygenated fuels, and it is also a regulated hazardous air pollutant. An improved understanding of its formation and destruction chemistry is therefore vital to the study of many energy conversion processes. To this end, this work experimentally and numerically investigates the flame chemistry of formaldehyde (CH2O) at atmospheric pressure. The laminar burning rate of 1,3,5-trioxane/O2/N2 mixtures is measured in outwardly propagating spherical flames, where high concentrations of formaldehyde are generated early in the flame structure from decomposition of 1,3,5-trioxane.
Though laminar burning rate predictions of several combustion …


Evaluation Of Thermal Radiation Effects On Apparent Propagation Rates Of High Pressure Spherical Flames, Jeffrey S. Santner, Francis M. Haas, Yiguang Ju, Frederick L. Dryer Sep 2013

Evaluation Of Thermal Radiation Effects On Apparent Propagation Rates Of High Pressure Spherical Flames, Jeffrey S. Santner, Francis M. Haas, Yiguang Ju, Frederick L. Dryer

Francis (Mac) Haas

Thermal radiation is usually not considered in the interpretation of laminar burning rates measured by the outwardly propagating spherical flame method. However, it may contribute significantly to measurement uncertainty, especially for model-constraining conditions at lower flame temperatures and higher pressures. The present work derives a conservative analytical estimate of the effects of radiation heat loss, which include radiation-induced burned gas motion, decreasing flame temperature due to conduction to the radiating burned gas, and radiation loss from the flame zone. Detailed numerical simulations covering a range of burning conditions serve to validate this analytical tool. Modeling results from both detailed simulation …


Towards Real-Time, On-Board, Hardware-Supported Sensor And Software Health Management For Unmanned Aerial Systems, Johann Schumann, Kristin Y. Rozier, Thomas Reinbacher, Ole J. Mengshoel, Timmy Mbaya, Corey Ippolito Sep 2013

Towards Real-Time, On-Board, Hardware-Supported Sensor And Software Health Management For Unmanned Aerial Systems, Johann Schumann, Kristin Y. Rozier, Thomas Reinbacher, Ole J. Mengshoel, Timmy Mbaya, Corey Ippolito

Ole J Mengshoel

Unmanned aerial systems (UASs) can only be deployed if they can effectively complete their missions and respond to failures and uncertain environmental conditions while maintaining safety with respect to other aircraft as well as humans and property on the ground. In this paper, we design a real-time, on-board system health management (SHM) capability to continuously monitor sensors, software, and hardware components for detection and diagnosis of failures and violations of safety or performance rules during the flight of a UAS. Our approach to SHM is three-pronged, providing: (1) real-time monitoring of sensor and/or software signals; (2) signal analysis, preprocessing, and …


Individual And Combined Effects Of Land Use/Cover And Climate Change On Wolf Bay Watershed Streamflow In Southern Alabama, Ruoyu Wang Sep 2013

Individual And Combined Effects Of Land Use/Cover And Climate Change On Wolf Bay Watershed Streamflow In Southern Alabama, Ruoyu Wang

Ruoyu Wang

Land use/cover (LULC) and climate change are two main factors affecting watershed hydrology. In this paper, individual and combined impacts of LULC and climate change on hydrologic processes were analysed applying the model Soil and Water Assessment Tool in a coastal Alabama watershed in USA. Temporally and spatially downscaled Global Circulation Model outputs predict a slight increase in precipitation in the study area, which is also projected to experience substantial urban growth in the future. Changes in flow frequency and volume in the 2030s (2016–2040) compared to a baseline period (1984–2008) at daily, monthly and annual time scales were explored. …


Rapport: Semantic-Sensitive Namespace Management In Large-Scale File Systems, Yu Hua, Hong Jiang, Yifeng Zhu, Dan Feng Sep 2013

Rapport: Semantic-Sensitive Namespace Management In Large-Scale File Systems, Yu Hua, Hong Jiang, Yifeng Zhu, Dan Feng

Yifeng Zhu

Explosive growth in volume and complexity of data exacerbates the key challenge to effectively and efficiently manage data in a way that fundamentally improves the ease and efficacy of their use. Existing large-scale file systems rely on hierarchically structured namespace that leads to severe performance bottlenecks and renders it impossible to support real-time queries on multi-dimensional attributes. This paper proposes a novel semantic-sensitive scheme, called Rapport, to provide dynamic and adaptive namespace management and support complex queries. The basic idea is to build files’ namespace by utilizing their semantic correlation and exploiting dynamic evolution of attributes to support namespace management. …


A Model For Calculating Acoustic Gravity Wave Energy And Momentum Flux In The Mesosphere From Oh Airglow, Gary R. Swenson, Alan Z. Liu Sep 2013

A Model For Calculating Acoustic Gravity Wave Energy And Momentum Flux In The Mesosphere From Oh Airglow, Gary R. Swenson, Alan Z. Liu

Alan Z Liu

Acoustic gravity and tidal waves propagating in the mesosphere/lower thermosphere (80-110 km) perturb the airglow layer intensities. The OH airglow has recently been modeled to determine the relationship between the relative perturbed atmospheric density and temperature (ρ’/ ρ, T’/T) to the OH intensity ( I’OH/IOH ) at the OH emission altitudes [Swenson and Gardner, 1997]. A model is presented here which relates wave perturbed OH airglow to the wave energy and momentum flux as they propagate through the emission layer. The model is dependent on the wave horizontal and vertical wavelengths (or phase speed as related through the dispersion relationship), …


Approximate Techniques For Dispersive Shock Waves In Nonlinear Media, Timothy R. Marchant, Noel F. Smyth Sep 2013

Approximate Techniques For Dispersive Shock Waves In Nonlinear Media, Timothy R. Marchant, Noel F. Smyth

Tim Marchant

Many optical and other nonlinear media are governed by dispersive, or diffractive, wave equations, for which initial jump discontinuities are resolved into a dispersive shock wave. The dispersive shock wave smooths the initial discontinuity and is a modulated wavetrain consisting of solitary waves at its leading edge and linear waves at its trailing edge. For integrable equations the dispersive shock wave solution can be found using Whitham modulation theory. For nonlinear wave equations which are hyperbolic outside the dispersive shock region, the amplitudes of the solitary waves at the leading edge and the linear waves at the trailing edge of …